The present invention relates generally to apparatus for purifying waste water and, more particularly, to such apparatus wherein the waste water is oxidized by the introduction of oxygen or an oxygen-containing gas in the presence of solid catalytic particles. The reaction, which may take place at ambient temperature and normal pressure, is preferably accomplished in a rectangular or square-shaped reaction basin or vessel which is open at the top. The reaction vessel includes a front wall and opposite back wall and two side walls. Inlet feed means are provided on the front wall for introducing waste water into the vessel. The vessel further includes outlet discharge means on the opposite back wall for discharging purified water from the vessel and a plurality of dividing walls which subdivide the vessel into a plurality of compartments or chambers. Each of the chambers include a pair of upwardly projecting risers interconnected by a plurality of angled or cocked partitions which form subchambers. The risers are positioned at a predetermined distance above the bottom of the reaction basin or vessel and terminate below the suface of the fluid which is to be contained in the vessel. A ventilating device may be provided below the risers in accordance with the teachings of, for example, West German Pat. No. P 31 26 078.0.
In accordance with the teachings of the present invention, the oxygen or oxygen-containing gas is adapted to contact the waste water from the bottom of the vessel and thereupon rise up through the water. The gas is uniformly directed in a predetermined pattern upwardly from the bottom of the vessel through the water. Equalization of the contact mass takes place automatically from chamber to chamber within the vessel with part of the contact mass being deposited at the bottom of the vessel. Due to the inflow of waste water, a vertical fluid flow is achieved in the region of the risers while a horizontal flow is achieved in the region of the bottom of the vessel.